Exhausting and gas filling machines for lamps



Jan. 27;- 1959 D. L. PEARSON ET AL 2,370,586v

EXHAUSTING AND GAS FILLING MACHINES FOR LAMPS Filed March 1, 1957 2 Sheets-Sheet 1 COMPRESSED lnveen tcrs: Donald L; Pearson, John D. Nelson,

b Mar 5 1;

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Their- Jan. 27, 1959 D. L. PEARSON ET AL 2,87

EXHAUSTING AND'GAS FILLING MACHINES FOR LAMPS Filed March 1, 1957 2 Sheets-Sheet 2 C V W I lnvevvtcws:

' Donatd L. Pearson,

John D. Nelson,

United States Patent C EXHAUSTING. AND GAS FILLING MACHINES FOR LAMPS Donald L. Pearson, Euclid, and John D. Nelson, Cleveland Heights, Ohio, assignors to General Electric Company, a corporation of New York Appl atio a h r a N 643 2 4 Claims. (01.53979 Our invention. relates to, automatic machines for exhausting and gas filling device such as electric lamps and more particularly to an automati machine for pressure filling and tipping ofi an electric lamp.

The total light output of electric photoflash lamps employing aluminum foil as the combustion material isdependent upon the weight of aluminum foil and the amount of oxygen present in the photofiash lamp. By increasing the weight of oxygen and the weight of aluminum foil in the photoflash lamp substantial gains in total light output can be realized. In order to increase the weight of oxygen present in the photoflash lamp the lamp must be filled with oxygen during manufacture to a pressure somewhat greater than existing atmospheric pressure.

In manufacture, it has been customary to evacuate the glass bulb through an exhaust tube, fill the bulb with gas, and then tip off the bulb by a fused seal; however, such usual methods of fabricating sealed glass bulbs are difiicult to use to accomplish the present purposes, because any attempt to seal off the bulb with above atmospheric gas pressure therein would result in the glass exhaust tu-be blowing out when softened by heat for sealing. As electric lamps are made on automatic machinery, the invention comprises an automatic machine for the manufacture of electric lamps, particularly electric photoflash lamps, whereby the lamp is tippedoif and sealed so as to contain pressure above atmospheric when in use. While the invention is described as relating to electric photofiash lamps, it is to be understood that the invention is directed toward automatic machinery for exhausting and gas filling the lamp and is not necessarily restricted to photoflash lamps.

An object of our invention is to provide an improved automatic machine for exhausting and gas filling electric lamps.

A more specific object of our invention is to provide an improved machine for exhausting and gas filling photoflash lamps containing an increased weight of oxygen therein.

Briefly stated, in accordance with one aspect of our invention, an automatic exhausting and gas filling machine, for example, that disclosed and claimed in U, S.

Patent No. 2,025,579, Donovan et al., and assigned to the same assignee as the present application, is modified to obtain pres-sure above atmospheric pressure in electric lamps after manufacture. After the electric lamp has been properly exhausted and flushed it is filled with atmospheric pressure and then cooled sufiiciently to be to openings 18 in a control valve 19.

2 below atmospheric pressure at time of tipping. When the lamp warms up to room temperature, the pressure within the lamp increases as compared to the low pressure at the time of tipping.

Further objects and advantages of our invention will become apparent as the following description proceeds and the features of novelty which characterize our invention will be pointed out with particularity in the claims annexed to and forming a part of this specification. stood when described in connection with the accompanying drawings, wherein Fig. 1 is a perspective View of a portion of an exhaust and gas filling machine showing the cooling and tipping off stations, Fig. 2 is a section through a cooling tank showing the electric lamp immersed up to neck level in cooling liquid, Fig. 3 is a modification of the invention similar to that shown in Fig. 1 but disclosing diagrammatically a refrigerant recirculation system, and Fig. 4 is a modification of the invention illustrating a modified cooling tank or trough.

Referr ng OW to Fig. 1 there is'shown diagrammatically a rotatable turret 1' of an exhaust machine to which the invention has been applied. In this instance there are shown but two exhaust headsZyhowever, it is to be understood that a similar exhaust head supports a bulb at each station. An electric lamp'bulb 3' is connected to the exhaust head by an exhaust tube 3a in the manner illustrated in the above identified Donovan patent. The oxygen gas passes into the body of the head through pipe 4'and passage 5 after passing through an oil, trap 6," whereas a vacuum line is connected through. pipe '7 and passage 8' which is connected directly to a rotary valve 9. The exhaust head 2 and lower portion 10 of the two section rotary valve 9 move with the turret while the upper section 11 of the rotary valve 9 is stationary. Bulb 3 remains securely fastened to the exhaust head 5:. asthe bulb 3 moves from station to station during indexing of the turret 1.

Coolant 13 is contained in a cooling tank 12 located under stations C through G of the turret. The cooling tank 12 is shown in raised position, but can move vertically upon rods 14 which pass downwardly, through guide bearings on the stationary frame 15 of the machine. The cooling tank 12 is moved up and down by an air cylinder 16 located below the center of the tank.

Control air for the cylinder 16 is admitted and discharged through openings 1'7 in the cylinder which are connected The control valve 19is actuated by a cam 2% on thernain cam or drive shaft 21 of the machine.

The main supply of coolant to the cooling tank 12 is an insulated coolant supply pipe 22 from which drips a coolant 13, such as liquid nitrogen, into a side channel 23 of the cooling tank 12. The refrigerant is supplied from an insulated carboy 24. Compressed air is supplied to the carboy 2 4 through air inlet pipe 25 after passing through a conventional air drier (not shown), a, pressure reducer 27 and a fiowgauge 26.

Preparatory to tipping off the bulb a series of preheat burners 28 are positioned on opposite sides of the lamp bulb to heat the exhaust tube. The preheat burners 28 may begin at one or'more stations before the bulb 3 is re moved from the cooling tank 12 and may extend one or more stations after the bulb 3 is removed from the cool; ing tank. A conventional tipping device, for example, such as that shown in Patent 1,929,313, Illingworth, and assigned to the same assignee as the present application, maybe used for sealing and tipping the bulb. Such tipping device 29 s ct ed b m. 3 dr en y hei e h ftzl. and act n -th ough lever ys em 3 h t pp ng device The nature of the invention will best be under- I grips the bulb 3 and separates it from the exhaust tube 3a causing the heated part of the exhaust tube to neck down and seal off the bulb.

The machine has a definite order of operation. After the bulb 3 is finally exhausted and pressure filled with the required amount of oxygen at stations A and B, the bulb, which is supported by the head 2, moves upon indexing of the turret 1 to station C. During the indexing of turret 1, cam 20 operates control valve 19 which in turn actuates the air cylinder 16 so as to lower the cooling tank 12 and permit the bulb 3 to advance from station B. to station C. Upon completion of the indexing the cooling tank 12 is then raised to its uppermost position so as to immerse the bulb in the coolant 13 contained within the cooling tank 12. The bulb 3 remains in the cooling tank during several dwell periods of the turret 1,

for example, here illustrated as stations C, D, E, F .and

G. The cooling tank 12 may extend under more or less than the five positions shown. The valve in the exhaust head 2 is closed ofi while the bulb 3 is in cooling positions so that the gas previously piped into the bulb is cooled and contracts down to below atmospheric pressure. As previously indicated, the preheat nozzles 28 are arranged on alternate sides of the bulb and are fired against the exhaust tube 3a so that the exhaust tube may be preheated before leaving the cooling tank 12. Preheating may continue for one or more dwell stations after the lamp leaves the cooling tank, for example, as

here illustrated at stations H and I. At station I the lamp 7 is sealed and tipped by the tipping mechanism 29 and the lamp bulb drops into chute 32 and is removed.

;Fig. 2 illustrates an enlarged cross-sectional view of the insulated cooling tank 12 showing a bulb 3 immersed in the coolant 13. A definite level 33 of the coolant must i It has been found that the above describedmethod and apparatus for cooling and reducing the pressure of the gas in the lamp bulb is especially suited for use with sealing and exhaust machines of a type currently in use.

Off hand, it might be supposed that the simultaneous or sequential cooling and heating to which the lamp bulb j and exhaust tube are subject would not result in any efiective lowering of the gas pressure within the bulb to make possible filling of the bulb with a greater weightof gas at an initial higher pressure. However, the coolant surrounds almost the entire glass bulb and hence cools almost the entire volume of gas within the bulb. This means that the pressure of the gas within the bulb is substantially reduced from the initial pressure applied by the filling head 2. At the same time, the preheat nozzles 28 are directed against only a small area of the exhaust tube 3a in which there is a very much smaller volume of gas. The result is that the heat generated by the nozzles 28, or their proximity to the coolant, have little adverse effect on the cooling action of the coolant on the lamp bulb. The tipping-ofi is accomplished easily and quicklywhile the lamp bulb is in a cooled condition with the gas pressure therein below atmospheric pressure. It has been found, for example, that when a bulb and head are previously filled with gas to ,a pressure of about 900 mm. of mercury the bulb may be cooled by the apparatus disclosed in the present invention. so as to reduce the gas pressure within the bulb and head to about,600 mm. of mercury during the tipping-0E process. Because only the bulb is immersed in coolant, as the oxygen pressure inside the bulb and head decreases, oxygen migrates from the head to the bulb producing much denser gas in the bulb. Therefore, when the bulb is separated from the 4 head during the tipping-off process, this greater quantity of oxygen is confined within the bulb with the result that when the completed bulb has warmed up to room temperature, the gas pressure inside the bulb may now be' 1000 mm. while that in the head remains at about A modification of the invention is illustrated in Fig. 3 wherein a recirculating system employing Freon'as a coolant is shown. The system is shown applied to an exhaust and gas filling machine similar to that illustrated in Fig. 1, such as the exhaust and gas filling machine of the above Donovan patent.

A closed circulating system dip tank cooled by a twostage cascade'refrigeration system is employed. The lamp bulb 3 is cooled by dipping into a coolant 34 contained within an inner tank 35. Any suitable coolant which does not leave undesirable residue on the bulb such as Freon-ll may be employed. Coolant 34 is cooled ,by a refrigerant 36, such as Freon-21 contained in an outer tank 37. The refrigerant 36 is pumped from a storage tank 38 by the circulating pump 39. The refrigerant 36 is drawn from the storage tank 38, passes through outlet 40 and into tank 37, returning to storage tank 38 through return line 41. The storage tank 38 is connected to tank 37 throughfiexible lines 42 and 43. The refrigerant 36 in the outer tank 37 is in heat exchanging relation with the refrigerant 34 contained in the inner tank 35. r

The refrigerating cycle shown diagrammatically consists of a compressor 44, a chilled condenser 45, and an expansion valve 46. The refrigerant in this cycle, which may be ethylene, is first compressed by the compressor 44, then passes as a high pressure vapor through conduit 48, is cooled in the chilled condenser 45, passes as a high pressure liquid through conduit 49, is expanded in the expansion valve 46, then passes through conduit to circulating coils (not shown) in the walls of the storage tank 38, and is returned as a low pressure vapor I through conduit 47 to the compressor 44. Cooling of the chilled condenser 45 is accomplished through a second stage cycle. The refrigerant in this cycle, which may be.Freon-22, is first compressed in a compressor 51, passes as a high pressure vapor through conduit 56 into an expansion valve wherein it is subjected to a pressure drop, and passes from the expansion valve 53 through conduit 57 into the condenser 45 wherein it is passed in heat exchanging relation with the ethylene or other refrigerant in the first stage cycle. The low pressure vapor passes from the chilled condenser 45 through condult 54 and is returned to the compressor 51.

In this manner the refrigerant from conduit 50 which is circulated through the cooling coils (not shown) in the storage tank 38 is in heat exchanging relation with the refrigerant 36 so as to cool the refrigerant 36'. The refrigerant 36 in turn is in heat exchanging relation with the coolant 34 in such a manner as to cool the coolant 34.

A further modification of the recirculating refrigeration system is illustrated in Fig. 4. A cold refrigerant, such as the refrigerant 36 from the storage tank' 38 shown in Fig. 3, may pass directly into an inlet conduit 58 contained within a cooling tank or trough 59. The inlet conduit 58 conducts the refrigerant 36 to jets or nozzles from which it is sprayed directly against the lamp bulb 3. The refrigerant which collects in the trough 59 is returned to the storage tank 38 through outlet conduit 61.

While We have described only certain preferred embodiments of our invention by way of illustration, many modifications will occur to those skilled in the art, for example the cooling tank or trough may have more or less than the five dwell stations shown, or the tipping ofi means may be at the first dwell station outside the tank, or preheating may occur at any reasonable number of dwell stations, or other coolants or refrigerants may be employed in place of liquid air, nitrogen, ethylene, Freon-11, Freon-21, and Freon-22, or the cooling tank may be raised and lowered mechanically rather than pneumatically, or the storage tank for coolant may be eliminated and the refrigerant from the two stage cascade refrigeration system may be in direct heat exchanging relation with the coolant in the cooling tank, or the coolant from the storage tank may be in direct contact with the lamp bulbs on the heads as, for example, if it were utilized in a drip tank. We, therefore, wish to have it understood that we intend in the appended claims to cover all such modifications as fall within the true spirit and scope of our invention.

What we claim as new and desire to secure by Letters Patent of the United States is:

1. A machine for gas filling and sealing a glass lamp bulb provided with a glass exhaust tube comprising, in combination, a rotatable turret mechanism for gripping a plurality of the exhaust tubes to move a plurality of the lamp bulbs in sequence to a series of work stations, said mechanism including means for gas filling the lamp bulbs at some of said work stations, means for cooling simultaneously a plurality of gas filled lamp bulbs, including a cooling tank movable into and out of engagement with the lamp bulbs as the turret mechanism rotates, means for heating part of the exhaust tube of at least one of the lamp bulbs while the bulb is immersed in said cooling tank, and means for separating the bulb from the heated part of the exhaust tube to seal off the bulb while the gas therein is still cool to reduce its pressure.

2. A machine for gas filling and sealing a glass lamp bulb provided with a glass exhaust tube comprising, in combination, a rotatable turret mechanism for gripping a plurality of the exhaust tubes to move a plurality of the lamp bulbs in sequence to a series of work stations, said mechanism including means for gas filling the lamp bulbs at some of said'work stations, means for cooling simultaneously a plurality of the gas filled lamp bulbs including a cooling tank movable into engagement with the lamp bulbs while said bulbs are at some of said work stations and movable down so as to be out of engagement with the lamp bulb as the turret mechanism rotates and so as to permit the lamp bulb to pass over the top of the tank as the turret mechanism indexes, means for heating part of the exhaust tube of one of the lamp bulbs while the bulb is in a cooled condition, and means for separating the bulb from the heated part of the exhaust tube to seal oil the bulb While the gas therein is still cool to reduce its pressure. it

3. A machine for gas filling and sealing a glass lamp bulb provided with a glass exhaust tube comprising, in combination, a rotatable turret mechanism for gripping a plurality of the exhaust tubes to move a plurality of the lamp bulbs in a curved path to a series of work stations, said mechanism including means for gas filling the lamp bulbs at some of said work stations, means for cooling simultaneously a plurality of the gas filled lamp bulbs including a cooling tank curved to substantially the same path followed by the lamp bulbs through the cooling work stations, means for moving said cooling tank upwardly into engagement with the lamp bulbs while the lamp bulbs are at the cooling work stations and downwardly out of engagement with the lamp bulbs as the turret mechanism rotates so that the lamp bulbs pass above the cooling tank during movement of the turret mechanism, means for heating part of the exhaust tube of one of the lamp bulbs while the bulb is in a cooled condition and means for separating the bulb from the heated part of the exhaust tube to seal oil the bulb while the gas therein is still cool to reduce its pressure.

4. A machine for gas filling and sealing a glass lamp bulb provided with a glass exhaust tube comprising, in combination, mechanism for gripping a plurality of the exhaust tubes to move a plurality of the lamp bulbs in sequence to a series of Work stations, said mechanism including means for gas filling the lamp bulbs at some of said work stations, means for cooling simultaneously a plurality of the gas filled glass bulbs including a cooling tank, means for heating part of the exhaust tube of one of the lamp bulbs while the bulb is in a cooled condition, and means for separating the bulb from the heated part of the exhaust tube to seal off the bulb while the gas therein is still cool to reduce its pressure.

References Cited in the file of this patent UNITED STATES PATENTS 1,831,935 Walker NOV. 17, 1931 

